The present invention relates to underlayments employed in applications such as roofing, walling, siding, or flooring, and more particularly to improved underlayments that increase the rate of water drainage by utilizing channels in the underlayment board.
The use of underlayments is well known for a variety of functions, such as thermal, noise, and air infiltration protection, moisture resistance, smooth surface creation, and hardiness. Typically, an underlayment is used to help reduce heating and cooling costs and provide a smooth, straight surface for the application of roofing, walling, foundations, siding or other exterior finish materials. The preferred application of the underlayment disclosed herein is for use as an underlayment to exterior finish materials, such as conventional siding materials, and other suitable uses where improved drainage is desired.
For new exterior finish materials applications, the underlayment boards provide a continuous air and moisture barrier for exterior finish materials such as vinyl, aluminum, steel, fiber cement, wood, or other suitable materials. For residing or existing applications, the underlayment is typically placed over the old siding to create a smooth level surface to improve installation and appearance.
Currently, at least one such underlayment is available from Pactiv Corporation under the name GreenGuard®, which is a foam board made of extruded polystyrene (XPS). Such underlayments generally known in the prior art are flat boards with substantially smooth planar surfaces.
In siding applications, the siding can be applied over the underlayment by nailing or screwing the siding into and through the underlayment and into the studs of the building. The nail or screw holes that result may allow wind blown rain to penetrate the siding. Vinyl siding may be interlocked together, but heavy rain may drive water around the joints. Additionally, other avenues of water penetration include seams or cracks along windows, doors, electrical fixtures, water faucets, weep holes and other penetrations in the sidings. Furthermore, power washing of siding or drainage systems can lead to further water penetrating the siding.
Therefore, there is a need for an underlayment having improved drainage.